I just wanted to let everyone know that we are aware of the issue editing tags on questions, blogs and links. That is that if you go to edit the tags of an existing item and try to remove a tag, it errors and you are ultimately unable to remove the tag. We are looking into the best way to address the problem now. So if you are one of those valuable moderators that likes to edit tags, I'm afraid you'll have to resign yourself to only adding tags and not removing any until we get this sorted.
Thanks for your patience!